If a three-phase motor runs backward after repair, which action should be taken?

• A. Change the location of 2 of the 3 leads
• B. Reverse the direction of the capacitor
• C. Check the voltage on the leads
• D. Decrease the amperage on all leads

Answer: (A)

In a three-phase motor, the direction of rotation is determined by the order of the three supply phases. If the phases come in the wrong sequence, the rotating magnetic field reverses and the rotor turns the opposite way. The standard way to fix this is to swap two of the supply leads, which changes the phase sequence and restores the correct direction of rotation. Before making any changes, power off the system and follow proper safety procedures.

Reversing a capacitor isn’t applicable for a typical three-phase motor, as they don’t rely on a capacitor for rotation like some single-phase motors do. Checking the voltage on the leads can help diagnose miswiring or supply issues, but it won’t correct the direction by itself. Decreasing amperage on all leads won’t fix the rotation and could cause underpower or damage.